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Combustion behaviour and emissions characteristics of different blending ratios of diesel and gasoline fuels (Dieseline) were investigated in a light-duty 4-cylinder compression-ignition (CI) engine operating on partially premixed compression ignition (PPCI) mode. Experiments show that increasing volatility and reducing cetane number of fuels can help promote PPCI and consequently reduce particulate matter (PM) emissions while oxides of nitrogen (NOx) emissions reduction depends on the engine load. Three different blends, 0% (G0), 20% (G20) and 50% (G50) of gasoline mixed with diesel by volume, were studied and results were compared to the diesel-baseline with the same combustion phasing for all experiments. Engine speed was fixed at 1800rpm, while the engine load was varied from 1.38 to 7.85 bar BMEP with the exhaust gas recirculation (EGR) application.

A life-cycle assessment (LCA) has been developed to help compare the economic, environmental and energy (EEE) impacts of converting coal to automotive fuels in China. This model was used to evaluate the total economic cost to the customer, the effect on the local and global environments, and the energy efficiencies for each fuel option. It provides a total accounting for each step in the life cycle process including the mining and transportation of coal, the conversion of coal to fuel, fuel distribution, all materials and manufacturing processes used to produce a vehicle, and vehicle operation over the life of the vehicle. The seven fuel scenarios evaluated in this study include methanol from coal, byproduct methanol from coal, methanol from methane, methanol from coke oven gas, gasoline from coal, electricity from coal, and petroleum to gasoline and diesel. The LCA results for all fuels were compared to gasoline as a baseline case.

The effective matching of the exhaust mufflers and engines is an important measure to reduce the noise emission of running vehicles. Currently, the matching is based mainly on the steady state performance of engine. The muffler's influence on a vehicle's noise emission and sound quality under different running conditions is not generally considered. A comprehensive performance evaluation method is proposed to describe the muffler's influence on a commercial vehicle's noise emission, sound quality and exhaust back pressure under multiple working conditions. The weighted insertion loss and linearity coefficient were defined based on the test data of the exhaust noise under different engine loads and speeds. A comprehensive performance evaluation method was defined from the test data analysis of engine exhaust noise with different mufflers. Finally, the simulation results of the exhaust noise of a vehicle with different mufflers were compared with test data.

Knocking is the main obstacle of increasing compression ratio to improve the thermal efficiency of gasoline engines. In this paper, the concept of stratified stoichiometric mixture (SSM) was proposed to suppress knocking in gasoline engines. The rich mixture near the spark plug increases the speed of the flame propagation and the lean mixture in the end gas suppresses the auto ignition. The overall air/fuel ratio keeps stoichiometric to solve the emission problem using three way catalysts (TWC). Moreover, both the rich zone and lean zone lead to soot free combustion due to homogeneous mixture. The effect on the knocking of homogeneous and stratified mixture was studied in a direct injection spark ignition (DISI) engine using numerical simulation and experimental investigation respectively.

Gasoline detergency is related to deposits at various parts of the engine and therefore has impact on vehicle driveability and emission properties. The widely used engine tests such as CEC F-20 M111 and ASTM D6201 Ford 2.3L tests take tens of hours and thus are very expensive and time consuming to carry out. A new simulation test for gasoline detergency on intake valve cleanliness using lean-oxygen gum method was developed and the correlation of test results with M111 engine test was studied. Gasoline samples with different detergency levels were tested with both the lean-oxygen gum method and the M111 engine test. Test results of 24 gasoline samples show satisfactory correlation between the lean-oxygen gum method and the M111 engine test (R₂=0.7258).

Coordinated EGR-VNT control based on the intake air mass observer is presented in this paper to deal with the transient AFR control of turbocharged diesel engine. The air mass model embedded in the observer is a Takagi-Sugeno fuzzy neural network trained with transient simulation results. It can predict the charged fresh air mass entering the cylinder. In a high load region, when EGR is not effective, the coordinated EGR-VNT control will also bring benefits to the transient air-fuel-ratio control. The simulation results of TDI engine model verify that the transient control strategy will allow a better control of the intake air mass, and thus improve air-fuel-ratio control and reduce NOx emission in transients.

A large proportion (about 33%) of the fuel energy is lost through exhaust gas in a gasoline engine. Electric turbo compounding (ETC) is a promising technology for gasoline engine exhaust energy recovery. In this paper, optimization of an ETC system for turbocharged gasoline engines is carried out. The ETC system has a turbo-generator that is in parallel with the turbocharger, the flow distribution between the turbocharger and the turbo-generator is controlled. The engine exhaust energy is recovered by the turbo-generator with fixed geometry turbine (FGT) or variable nozzle turbine (VNT). The design and control of the ETC system are optimized for best recovery of engine exhaust energy at engine full load and part load operating conditions. The system performance is studied by 1D simulation methods. The gasoline engine is modeled with the GT-POWER software and the turbochargers and turbo-generators are modeled with turbo through-flow models.

Compared with conventional vehicles, electric vehicles (EVs) offer the benefits of replacing petroleum consumption and reducing air pollutions. However, there have been controversies over greenhouse gas (GHG) emissions of EVs from the life-cycle perspective in China’s coal-dominated power generation context. Besides, it is in doubt whether the cost-effectiveness of EVs in China exceeds other fuel-efficient vehicles considering the high prices. In this study, we compared the life-cycle GHG emissions of existing vehicle models in the market. Afterwards, a cost model is established to compare the total costs of vehicles. Finally, the cost-effectiveness of different vehicle types are compared. It is concluded that the GHG emission intensity of EVs is lower than reference and hybrid vehicles currently and is expected to decrease with the improvement of the power grid.

With increasingly stringent requirements and regulations related to particulate matter(PM) emissions, manufacturers are paying more and more attention to emissions from gasoline direct injection(GDI) engines. The present paper proposes an improved two-step soot model. The model is applied in the Kiva-Chemkin program to simulate the processes of spray impinging, fuel mixture preparation, combustion and soot formation in a typical turbocharged downsized GDI engine. The simulation results show that soot formation in the GDI engine is attributed to non-uniform distribution of the air-fuel mixture and pool fire of wall film in the cylinder. Under homogeneous mode, increasing the injection advance angle can optimize fuel atomization and improve air-fuel mixing, thus reducing soot formation. However, an excessive injection advance angle may cause spray to impinge on the cylinder wall and this will sharply increase the soot emission.

Particle Number (PN) have already been a big issue for developing high efficiency internal combustion engines (ICEs). In this study, controlled spark-assisted stratified compression ignition (SSCI) with moderate end-gas auto-ignition was used for reducing PN in a high compression ratio gasoline direct injection (GDI) engine. Under wide open throttle (WOT) and Maximum Brake Torque timing (MBT) condition, high external cooled exhaust gas recirculation (EGR) was filled in the cylinder, while two-stage direct injection was used to form desired stoichiometric but stratified mixture. SSCI combustion mode exhibits two-stage heat release, where the first stage is associated with flame propagation induced by spark ignition and the second stage is the result of moderate end-gas auto-ignition without pressure oscillation at the middle or late stage of the combustion process.

Coke oven gas (COG) is a byproduct of coking plants in steel mills which can be methanized resulting in a hydrogen-methane mixture with a volumetric fraction of roughly 55% hydrogen (roughly 13.25% by mass) and 45% methane (roughly 86.75% by mass). In order to simulate the use of coke oven gas as a fuel for engines, this study focuses on hydrogen enriched compressed natural gas (HCNG) at a hydrogen volumetric fraction of 55%, which is the same content as the methanized COG. The power, efficiency and emissions characteristics are outlined at different load conditions which will be provided for the next step electronic control, performance optimization and product development research. This potential alternative fuel has the potential not only to reduce engine emissions, but will also help reduce the waste COG produced in large quantities by factories across the world.

Selective catalytic reduction (SCR) is a promising technology for diesel aftertreatment used to reduce NOX emission effectively. SCR can be used to meet Euro - and even stricter emission standards. Dosing of urea must be controlled to lower NOX emission and NH₃ slip synchronously under the emission standard limits. A type of closed-loop control strategy based on NOX sensors for SCR system was presented in this paper. To detect NOX emissions, two NOX sensors were installed before and after the catalyst. Meanwhile, to examine the trade-off relationship between NOX emission and NH₃ slip, influences of different control parameters to the control purpose were explored. These influences include space velocity, catalyst temperament, NOX conversion efficiency, NH₃ adsorption and desorption characteristics, and so on. Results were used to optimize the dosing control strategy of urea. Base dosage of urea was confirmed based on the signals of NOX sensor.

In-cylinder pressure sensor, which provides the means for precise combustion control to achieve improved fuel economy, lower emissions, higher comfort, additional diagnostic functions etc., is becoming a necessity in future diesel engines, especially for chemical-kinetics dominated PCCI (Premixed Charge Compression Ignition) or LTC (Low Temperature Combustion) engines. In this paper, new control strategy is investigated to utilize in-cylinder pressure information into engine start process, in order to guarantee the success of engine start and in the meantime prevent penalty of fuel economy or pollutant emissions due to excessive fuel injection. An engine start acceleration model is established to analyze the engine start process. “In-cylinder Combustion Analysis Tool” (i-CAT), is used to acquire and process the in-cylinder pressure data and deliver the combustion indices to ECU (Engine Control Unit). Feedback control is accomplished in ECU based on this information.

An experimental study of particulate matter and volatile organic compounds (VOCs) emissions was conducted on a direct injection gasoline (DIG) engine and a port fuel injection (PFI) engine which both were produced by Chinese original equipment manufacturers (OEMs) to investigate the impact of fuel properties from Chinese market on particulate and VOCs emissions from modern gasoline vehicles. The study in this paper is just the first step of the work which is to investigate the impact of gasoline fuel properties and light duty vehicle technologies on the primary and secondary emissions, which are the sources of particulate matter 2.5 (PM2.5) in the atmosphere in China. It is expected through the whole work to provide some suggestions and guidelines on how to improve air quality and mediate severe haze pollution in China through fuel quality control and vehicle technology advances.

The influence of the catalyst loading, the active components, and the size of the pellets on the conversion were discussed. Over a CeCuM′M″ catalyst at 25000h-1 the CO could be oxidized about 53.4% at 150°C. The radial distribution of the rare earth Ce, and the transitional metals M′ and M″ were homogeneous, but Cu increased gradually from the centre to outside of the pellets.

The effect of several aqueous metal-salt solutions on NOx and smoke lowering in an IDI diesel engine were examined. The solutions were directly injected into a divided chamber independent of the fuel injection. The results showed that significant lowering in NOx and smoke over a wide operation range could be achieved simultaneously with alkali metal solutions which were injected just prior to the fuel injection. With sodium-salt solutions, for instance, NOx decreased by more than 60 % and smoke decreased 50 % below conventional operation. The sodium-salt solution reduced dry soot significantly, while total particulate matter increased with increases in the water soluble fractions.

This paper presents a dual fuel system for diesel-natural gas operation for a truck diesel engine, and describes results of testing and analysis of the operating characteristics of the engine. The research results show that rates of fuel consumption and fuel efficiencies are increased with this engine design, and heat consumption decreased with increasing load on the engine. The heat consumption rates at medium-high loads are lower than at light loads. At full loads, the dual fuel engine exhibits heat release in which start combustion is reduced and the following combustion is rapid. The engine is tested with an electronically controlled method to meet the requirement of engine output torque.

A 1-Dimensional (1-D) model of fluid dynamic and chemistry kinetics following hot spot auto-ignition has been developed to simulate the process from auto-ignition to pressure wave propagation. The role of wall effect on the physical-chemical interaction process is numerically studied. A pressure wave is generated after hot spot auto-ignition and gradually damped as it propagates. The reflection of the wall forms a reflected pressure wave with twice the amplitude of the incident wave near the wall. The superposition of the reflected and forward pressure waves reinforces the intensity of the initial pressure wave. Wall effect is determined by the distance between the hot spot center and the cylinder wall. Hot spot auto-ignition near the wall easily initiates detonation under high-temperature and high-pressure conditions because pressure wave reflection couples with chemical reactions and propagates in the mixture with high reactivity.

n-butanol has been recognized as a promising alternative fuel for gasoline and may potentially overcome the drawbacks of methanol and ethanol, e.g. higher energy density. In this paper, the spray characteristics of gasoline and n-butanol have been investigated using a high pressure direct injection injector. High speed imaging and Phase Doppler Particle Analyzer (PDPA) techniques were used to study the spray penetration and the droplet atomization process. The tests were carried out in a high pressure constant volume vessel over a range of injection pressure from 60 to 150 bar and ambient pressure from 1 to 5 bar. The results show that gasoline has a longer penetration length than that of n-butanol in most test conditions due to the relatively small density and viscosity of gasoline; n-butanol has larger SMD due to its higher viscosity. The increase in ambient pressure leads to the reduction in SMD by 42% for gasoline and by 37% for n-butanol.

A study of Multiple Premixed Compression Ignition (MPCI) with heavy naphtha is performed on a light-duty single cylinder diesel engine. The engine is operated at a speed of 1600rpm with the net indicated mean effective pressure (IMEP) from 0.5MPa to 0.9MPa. Commercial diesel is also tested with the single injection for reference. The combustion and emissions characteristics of the heavy naphtha are investigated by sweeping the first (−200 ∼ −20 deg ATDC) and the second injection timing (−5 ∼ 15 deg ATDC) with an injection split ratio of 50/50. The results show that compared with diesel combustion, the naphtha MPCI can reduce NOx, soot emissions and particle number simultaneously while maintaining or achieving even higher indicated thermal efficiency. A low pressure rise rate can be achieved due to the two-stage combustion character of the MPCI mode but with the penalty of high HC and CO emissions, especially at 0.5MPa IMEP.